1 . Field of Invention
The invention relates to methods and systems for performing stress testing of equipment. The invention also relates to active and passive stress testing using modular design and robust data collection that is adaptable to a variety of equipment.
2 . Description of Related Art
It is common to subject integrated circuits (IC) to various stresses to ensure reliability. Specifically, an IC is typically subjected to high temperatures for an extended period of time. This process is called xe2x80x9cbum-inxe2x80x9d testing in the art and identifies marginal devices likely to succumb to such stresses in the field.
Various systems and methods have been designed to perform burn-in testing of integrated circuits and computer components. Many of these conventional solutions focus on specific adapters and hardware that permit high-volume bum-in testing of specific equipment.
For example, Slocum (U.S Pat. No. 6,097,201) discloses a system of stackable test boards in which a large number of integrated circuit boards may be mounted. Each of Slocum""s test boards includes a contactor region that permits test signals to be routed to the individual integrated circuit boards. As such, Slocum""s system is specifically designed to perform high-volume burn-in testing of specific components (integrated circuit boards).
Leung (U.S. Pat. No. 5,798,653) utilizes a special-purpose burn-in controller located within the burn-in oven to xe2x80x9cexercisexe2x80x9d an integrated circuit (IC) by toggling a high percentage of the switches within the IC.
Leung also illustrates the conventional thinking of burn-in testing which is to select a statistically significant sample of the product (IC""s in this case) which are then subjected to burn-in testing. Like Slocum, Leung""s system performs a dynamic test in which input stimuli are applied to the ICs to exercise or toggle the electrical circuit nodes of the IC.
Leung performs two types of dynamic burn-in testing on these sample IC""s including an infant mortality burn-in and a longevity qualifying burn-in which mainly differ in the amount of time in which the IC""s are subjected to the age-accelerating burn-in test. A simple data set is collected from these tests, which includes how many ICs succumb to infant mortality.
The flexibility of conventional stress testing systems is quite limited. Moreover, the number testing circuits matches the number of IC boards being tested thus requiring duplicative testing hardware. Moreover, the data collected by conventional system is quite rudimentary. Thus, there is a need in the art that solves these and other deficiencies in conventional stress-testing systems.
The present invention brings revolutionary concepts to the field of stress testing: utilizing a virtual oven, sharing test equipment, and logically grouping components and modules to be tested provides many distinct advantages over the prior art.
In general, the inventive systems and methods solve the problem of massive manual management of the following: a) process control, b) data, c) active signal controls, and d) product performance verification for stress testing. This goal was accomplished by designing, developing, and making operational an Automated Monitoring System (AMS). AMS communicates to modules and test equipment that are undergoing and performing stress testing as well as collecting the data automatically.
Stress testing according to one aspect of the invention includes exposing operating equipment/modules to thermal stress (or other stressor(s)) over a long (e.g. 48 hour) period of time including an (e.g. 24 hour) active test such as a bit error rate test (BERT) for optically tested modules (e.g. transmitters, receivers, remodulators, selectors, transceivers, variable optical attenuators, and amplifiers). The stress tests may also involve introducing noise to the test signal and/or degrading the test signal strength. The invention is capable of testing a wide variety of other components including electronic, opto-electronic, and optical components.
The inventive stress-testing process is a critical component of the manufacturing flow for producing reliable modules because the invention:
Reveals module damage due to handling (e.g. electrostatic discharge or other handling related damage).
Virtually simulates field conditions over a broad range of temperatures, operating conditions, and signal conditions.
Deliberately ages the product so as to eliminate substantially all early life failures from the product shipped to the customer.
More specifically, virtual oven for stress testing a plurality of modules includes a logical group of modules loaded into an environmental stress screening room wherein an environmental stress parameter of the environmental stress screening room changes over time; a test equipment operatively connected to the modules of said logical group, said test equipment generating a test signal and capable of performing an active test of at least one of the modules of said logical group at a time; and a controller operatively connected to said test equipment and to said logical group of modules; said controller receiving results of the active test performed by said test equipment.
The modules may also include sensors or other devices for measuring parameters of the module and the controller may receive passive test measurement values from these sensors. In this way, a passive test of the modules may be performed independently of and simultaneous with the active testing. The results of the active test and the passive test measurement values for each of the modules are associated with the module and stored in a database.
Furthermore, the controller may send a command to at least one module of the logical group to, for example, place that module in a desired operational state, exercise the module, or otherwise assist in the testing regime.
Moreover, a network may be used to operatively connect the test equipment with the controller, the memory device, and each of the modules of the logical group. The invention also includes a system of virtual ovens that may be connected via a network.
The inventive methods for stress-testing a plurality of modules includes designating a logical group of modules in an environmental stress screening room wherein an environmental stress parameter of the environmental stress screening room changes over time; generating a test signal; supplying the test signal to at least one of the modules of the logical group to subject the at least one module to an active test thereof, and receiving results of the active test from one of the modules of the logical group with a test equipment.
The method may perform a series of tests of the logical group modules on a time-share basis with the test equipment. In addition, the method may further include receiving passive test measurement values from at least one of the modules of the logical group; analyzing the passive test measurement values and the active test results; and displaying results of said analyzing step.
Moreover, the invention encompasses a method of asynchronously conducting stress testing on a plurality of groups modules including a first and second logical groups of modules. This method asynchronously initiates testing of the first and second logical groups of modules; tests the first logical group of modules with the first test equipment; and tests the second logical group of modules with the second test equipment, wherein each of said testing steps respectively includes said generating step, said supplying step, and said receiving step.
The inventive methods also include receiving passive test measurement values from at least one of the modules of the logical group; and storing results of the active test and the passive test measurement values for each of the modules in the database.
Moreover, the modules comprising the logical groupings are not necessarily physically adjacent to one another.
The inventive virtual oven system may also utilize an inventive database. In particular, the database invention includes a stress-test information database stored in a computer-readable medium and usable for storing information related to a stress-test of different products, comprising: a product data entity storing product-specific information for a plurality of the different products that may be subjected to the stress-test; a process data entity storing testing process information for conducting one or more stress-test processes of the stress-test; a result data entity storing stress-test result information relating to one or more results of the stress-test processes; a product-result map relating said product data entity to said result data entity; and a process-result map relating said process data entity to said result data entity.
The stress-test information database may further include, particularly when a plurality of equipment is utilized to conduct the stress-test, the following elements: a command data entity storing command information that may be utilized to command the equipment; and an equipment data entity storing information relating to the equipment; said equipment data entity being associated with said command data entity to permit a variety of equipment-specific command information to be retrieved.
The command data entity may include a generic command data entity storing information relating to generic commands usable to conduct the stress test processes and an equipment command string data entity usable for translating generic commands to equipment-specific commands, said generic command data entity being associated with said equipment command string data entity; and said equipment data entity being associated with said command data entity, wherein a generic command may be translated into an equipment-specific command via the associations between said generic command data entity, said equipment command string data entity, and said equipment data entity.
In addition, the stress-test database may further include: a parsing table storing information relating to parsing of equipment-specific data received as a result of the stress test; said parsing table being associated with said equipment data entity to permit the equipment-specific data to be parsed into a more consistent format suitable for storage by said result data entity.
If the database is used with the virtual oven invention discussed above, it is advantageous to fither include a virtual oven data entity storing information relating to one or more virtual ovens that may be utilized to conduct the stress test. More particularly, the process data entity may include: a process information item storing information relating to stress test process identity and test process description; a process test run data entity storing information relating to stress test process identity, virtual oven identity and stress test process start/stop time(s); and a virtual oven data entity storing information relating to virtual oven identity, virtual oven description and virtual oven location, said process test run data entity relating said virtual oven data entity to said process information item in order to permit functional associations between virtual ovens, stress test processes, and process-test runs.
Moreover, the stress-test database may also include a test criteria data entity storing information relating to stress-test criteria, said test criteria data entity being associated with said result value data entity, said result value data entity item further including a pass/fail information item, said result value data entity and said test criteria data entity being usable to determine whether the product has passed or failed one or more of the stress-test processes.
In addition, an inventive method of storing information related to a stress-test of different products in a computer-readable stress-test information database is disclosed and includes: storing product-specific information for a plurality of the different products that may be subjected to the stress-test in a product data entity; storing testing process information for conducting one or more stress-test processes of the stress-test in a process data entity; storing stress-test result information relating to one or more results of the stress-test processes in a result data entity; relating the product data entity to the result data entity with a product-result map; and relating the process data entity to the result data entity with a process-result map.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.